When a transition is created for the allocation change, it will delay
the new allocation box getting set depending on transition details.
This, however, means that e.g. the 'needs_allocation' flag never gets
cleared if a transition is created, causing other parts of the code to
get confused thinking it didn't pass through a layout step before paint.
Fix this by calling clutter_actor_allocate_internal() with the current
allocation box if a transition was created, so that we'll properly clear
'needs_allocation' flag.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1345
Test that the stage-views list of ClutterActor is correct when moving an
actor, reparenting it, or hiding an actor up the hierarchy. Also test
that the "stage-views-changed" signal works as expected.
Don't test actor transforms for now because those aren't supported yet.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1196
